The main objectives of this proposal are to maintain an animal resource to promote, encourage, and expedite research into human prostatic adenocarcinoma. Prostate cancer is the second leading cause of cancer deaths in men with over 122,000 new cases estimated to occur in 1991 and over 32,000 deaths. The resource has been in continuous existence for the past 15 years. Breeding colonies of Copenhagen line 2331 and Fischer F344 are maintained in a virus-free state. They are mated to produce an F1 hybrid. F1 animals are then inoculated with a hormone-responsive spontaneous rat prostatic adenocarcinoma, R3327 for various human health related research projects. Dr. Wilhelmena Dunning first described this spontaneous prostatic adenocarcinoma (R3327) in 1962. Since that time, it has been extensively characterized morphologically, biochemically, and immunologically. This grant will allows us to maintain this resource and to provide tumor bearing rats and/or tumor tissue to investigators for pilot projects. Because of the biological characteristics of this tumor including its slow growth rate, it would take an investigator approximately 18 months to gear-up for a pilot project without this resource. We are able to supply tumor bearing rats to investigators approximately 4-6 weeks after the request. This results in a considerable cost saving to NIH as well as to investigators. Additionally, a centralized resource reduces the numbers of animals which have to be maintained thereby assisting NIH in their goal of reducing the total numbers of animals used in research.